Many weight loss programs lose their effectiveness with time - relapses are all too common, both with dietary and exercise plans. Any approach to get people to "stick with the program" over a period of time is to be encouraged. This US study looked at the effectiveness of two alternatives to traditional endurance (aerobic) exercise - short bouts of daily exercise, and the use of a treadmill at home.

Women, recruited by newspaper advertisements, were enrolled if they were between 25 and 45 and had body weights 20% to 75% greater than their ideal weight. They had to have sedentary jobs, and have no medical conditions or be taking medications that would interfere with their participation in an exercise program.

All the exercise routines were done at home - brisk walking or something similar (e.g. running, bicycling). The women were randomly assigned to one of 3 groups. The total amount of exercise done was the same in each group. A "long-bout exercise" group (LB Group) exercised 5 days a week, for 40 minutes a day in one continuous session. A "short-bout" group (SB Group) exercised 5 days a week for 40 minutes each day, but the exercise was divided into 10-minute sessions performed at convenient times during the day. The third group (SBEQ Group) had the same program as the SB Group, but the members were provided with motorized home treadmills.

The study period was 18 months. During this time exercise levels were increased gradually during the first 8 weeks to the required total amount. Participants attended group meetings (weekly at first, then twice monthly, and finally monthly) that discussed modification of eating habits and attitudes to exercise. Everyone agreed to follow prescribed calorie and fat intake restrictions, and to keep a food diary, which was evaluated weekly by a dietician.

Body weight was measured at the start of the study, and after 6, 12 and 18 months. Cardiorespiratory fitness was assessed at baseline, 6 and 18 months. Participants recorded their exercise in an exercise log, along with leisure-time physical activity.

A total of 115 subjects completed the 18-months. After 6 months all 3 groups had lost weight (an average of 22 lb), with no significant differences between the groups. After 12 months, the LB Group and the SB Group had regained some weight, while the SBEQ Group continued to lose weight. In the next 6 months, all three groups regained weight, in spite of continued exercise and dieting. However, at the end of the study (18 months) the short-bout group with a home treadmill (the SBEQ Group) had regained significantly less weight than the short-bout group without a treadmill (the SB Group): on average 4lb (1.8 kg) compared to 9 lb (4.1 kg). Final average weight losses in the three groups were as follows: LB Group 16.7 lb (7.6 kg), SB Group 11.4 lb (3.7 kg), and SBEQ Group 18.5 lb (8.4 kg).

The time spent exercising, taken from the exercise logs, peaked for all three groups during the 3rd to 6th month. After that, there was a considerable fall-off in activity in the LB and SB Groups; the SBEQ Group members also decreased their activity level, but significantly less than those in the other two groups.

This study showed that the doing short exercise sessions at intervals during the day doesn't ensure that people stick to their exercise program any better than doing a more traditional 40-minute continuous program. However, having a treadmill in the home increased the actual performance and the effectiveness of the short-bout program. Weight loss over an 18-month period was somewhat greater when the treadmill was available. Any step that produces a better outcome in weight loss programs should be included, where possible. Several short exercise sessions at home using a treadmill is likely to be more attractive than a 40-minute running, walking or bicycling regime, for quite a number of older candidates.

Source

Effects of intermittent exercise and use of home exercise equipment on adherence, weight loss, and fitness in overweight women: a randomized trial.
JM. Jakicic, C. Winters, W. Lang, RR. Wing, JAMA, 1999, vol. 282, pp. 1554--1560